Ultraviolet absorbers are formulated in cosmetics for the purpose of protecting bare skin from ultraviolet rays. These ultraviolet absorbers may be roughly classified into organic types and inorganic types. Examples of the former include cinnamic acid derivatives, benzophenone derivatives, methylaminobenzoic acid derivatives and salicylic acid derivatives. Examples of the latter include metal oxides such as zinc oxide, titanium oxide, cerium oxide and iron oxide. In the case of organic ultraviolet absorbers, there is the problem that these absorbers have a low absorption wavelength region, are constituted of unstable compounds and penetrate into the skin so that the effect of these absorbers does not last long. In the case of inorganic ultraviolet absorbers, there is the problem that these absorbers have less dispersibility in a product formulation and not much good feeling in use.
Capsulation of metal oxides is known as one proposal for making compatible dispersibility in a product formulation and a good feeling in use. For example, in JP-A 9-208437, a cosmetic is disclosed which is prepared by coating a metal oxide having an average particle diameter of 0.003 to 0.1 μm with a resin powder, in an emulsion cosmetic. However, because an ionic dispersant is used to disperse the metal oxide in this method, the hydrophilic portions of the metal oxide aggregate in the W/O emulsion cosmetic in the case where the metal oxide partly exists on the surface of the resin powder, and therefore the stability of the formulation is impaired and protection from ultraviolet rays is ineffective.
Also, in another attempt, studies have been made concerning cosmetics combining protection from ultraviolet rays and a good feeling in use by using a combination of several powders. For example, in JP-A 9-235217, cosmetics containing inorganic powders are disclosed in which silica having a particle diameter of 0.01 to 10 μm is coated with zinc oxide, and in which a super-microparticle titanium oxide having a particle diameter of 0.001 to 0.10 μm is coated with a plate talc, mica and/or sericite.
However, when the resin powder in which these metal oxides are coated is used alone or in combination with a super-microparticle titanium oxide, a cosmetic having an effective UVA protection and a good feeling in use cannot be obtained.